Quenching processes of aromatic hydrocarbons in the higher triplet excited states-energy transfer vs. electron transferElectronic supplementary information (ESI) available: The quenching of DBA(Tn) by CCl4, CHR(Tn) by NAP, the evidences of no DBA and CHR ions produced during two-color two-laser flash photolysis, and the evidence of formation of benzene/Cl complex. See http://www.rsc.org/suppdata/cp/b4/b400128a/

2004 ◽  
Vol 6 (8) ◽  
pp. 1735 ◽  
Author(s):  
Xichen Cai ◽  
Masanori Sakamoto ◽  
Michihiro Hara ◽  
Sachiko Tojo ◽  
Kiyohiko Kawai ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Excited States ◽  
Aromatic Hydrocarbons ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Supplementary Information ◽  
Triplet Excited States

scholarly journals Dynamics of small molecules within the F127 PEO-PPO-PEO triblock copolymer gel and sol phases studied at the molecular scale

2022 ◽  
Author(s):  
Suma S. Thomas ◽  
Helia Hosseini-Nejad ◽  
Cornelia Bohne
Keyword(s):  
Excited States ◽  
Rate Constants ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Supramolecular System ◽  
Quenching Rate ◽  
Naphthalene Derivatives ◽  
Decay Rate Constant ◽  
Triplet Excited States

The dynamics of naphthalene derivatives with different hydrophobicities bound to F127 polyethyleneoxide-polypropyleneoxide-polyethyleneoxide (PEO-PPO-PEO) micelles in the gel and sol phases were studied using a quenching methodology for the triplet excited states of the naphthalenes. Studies with triplet excited states probe a larger reaction volume than the volumes accessible when using fluorescent singlet excited states. The use of triplet excited states enables the determination of the dynamics between different compartments of a supramolecular system, which in the case of F127 micelles are the micellar core, the micellar corona and the aqueous phase. This report includes laser flash photolysis studies for the four naphthalene derivatives in the F127 gel and sol phases. The triplet excited states were quenched using the nitrite anion as the quenchers. The association and dissociation rate constants of the naphthalenes from the micelles and the quenching rate constants for the naphthalenes bound to the micelles were determines from the curved quenching plot (observed decay rate constant vs. nitrite concentration).

First Direct Observation of the Higher Triplet Excited States of Substituted Oligothiophenes by Two-Color Two-Laser Flash Photolysis

ChemPhysChem ◽  
2004 ◽  
Vol 5 (8) ◽  
pp. 1240-1242 ◽  
Author(s):  
Mamoru Fujitsuka ◽  
Yosuke Oseki ◽  
Michihiro Hara ◽  
Xichen Cai ◽  
Akira Sugimoto ◽  
...  
Keyword(s):  
Excited States ◽  
Direct Observation ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Triplet Excited States

Reduction of hexaammineruthenium(III) ions by a series of tris(polypyridyl)chromium(II) ions – Revisiting the Cr(NN)33+/2+ self-exchange rate

2001 ◽  
Vol 79 (7) ◽  
pp. 1124-1127 ◽  
Author(s):  
K Omar Zahir
Keyword(s):  
Exchange Rate ◽  
Excited States ◽  
Rate Constants ◽  
Driving Force ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Outer Sphere ◽  
Laser Flash ◽  
Exchange Rate Constant ◽  
Kinetics Of

The kinetics of the outer-sphere oxidation of Cr(NN)32+ ions (NN = 2,2'-bipyridine, 1,10-phenanthroline, and their substituted analogs) by hexaammineruthenium(III) was studied using laser flash photolysis. The Cr(NN)32+ ions were generated via the reductive quenching of the *Cr(NN)33+ excited states by oxalate ions or by H2edta2–. The second-order rate constants were found to vary with the driving force of the reaction. The rate constants increase from (7.1 ± 0.5) × 106 M–1 s–1 for Cr(5-Clphen)32+ to (2.6 ± 0.2) × 108 M–1 s–1 for Cr(4,7-Me2phen)32+. The self-exchange rate constant for the couple (Cr(NN)33+/2+) was calculated by applying Marcus cross relation to present and other known reactions of Cr(NN)3n+ ions, where n = 3 or 2 with various reactants and is estimated to be (6 ± 4) × 107 M–1 s–1.Key words: tris(polypyridyl)chromium(II)/(III) self-exchange rate, hexaammineruthenium(III), oxidation of Cr(NN)32+.

Energy-transfer studies on phthalocyanine–BODIPY light harvesting pentad by laser flash photolysis

2015 ◽  
Vol 19 (01-03) ◽  
pp. 261-269 ◽  
Author(s):  
Mohamed E. El-Khouly ◽  
Cem Göl ◽  
Morad M. El-Hendawy ◽  
Serkan Yeşilot ◽  
Mahmut Durmuş
Keyword(s):  
Energy Transfer ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Visible Region ◽  
Geometry Optimization ◽  
Laser Flash ◽  
Zinc Phthalocyanine ◽  
Nanosecond Laser ◽  
Artificial Photosynthetic ◽  
Photosynthetic Antenna

A molecular pentad, comprised of zinc phthalocyanine ( ZnPc ) with four boron dipyrromethene units (BODIPY) have been examined by femtosecond and nanosecond laser flash photolysis to explore its photoinduced intramolecular events from the excited BODIPY. The geometry optimization showed that the phthalocyanine moiety is completely symmetric and form perfect square planar complex with zinc. The absorption spectrum of ZnPc -BODIPY pentad covers most of the visible region (ca. 300–750 nm), which clearly is an advantage for capturing solar energy. The excitation transfer from the singlet BODIPY to ZnPc is envisioned due to good spectral overlap of the BODIPY emission and ZnPc absorption spectra. Femtosecond laser flash photolysis studies provided concrete evidence for the occurrence of energy transfer from the singlet excited BODIPY to ZnPc in tetrahydrofuran. The kinetic study of energy transfer measured by monitoring the decay of the BODIPY emission revealed fast energy transfer (5.90 × 1010 s-1) in the molecular pentad. Since the electron transfer from the singlet ZnPc to BODIPY is thermodynamically not feasible, the singlet ZnPc decayed to populates the triplet ZnPc , in addition to the grounds state. These findings suggest the potential of the examined ZnPc -BODIPY pentad to be efficient photosynthetic antenna in the artificial photosynthetic systems.

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